Power Calculation 3 Phase Motor

3-Phase Power Formula:

\[ P_{kW} = \frac{V \times I \times PF \times \sqrt{3}}{1000} \]

Power (P_kW): kW

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1. What is 3-Phase Motor Power Calculation?

Definition: This calculator determines the real power (in kW) consumed by a 3-phase AC motor based on voltage, current, and power factor.

Purpose: It helps electrical engineers, technicians, and maintenance personnel assess motor performance and energy consumption.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ P_{kW} = \frac{V \times I \times PF \times \sqrt{3}}{1000} \]

Where:

\( P_{kW} \) — Real power in kilowatts
\( V \) — Line-to-line voltage (volts)
\( I \) — Line current (amps)
\( PF \) — Power factor (0 to 1)
\( \sqrt{3} \) — Constant for 3-phase systems

Explanation: The formula calculates the actual power being used (real power) as opposed to the apparent power (VA).

3. Importance of Power Calculation

Details: Accurate power calculation helps in sizing electrical components, assessing energy efficiency, and troubleshooting motor issues.

4. Using the Calculator

Tips: Enter the line voltage (typically 208V, 230V, 460V, etc.), measured current, and power factor (default 0.85). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, ranging from 0 to 1. It represents how effectively current is being converted into useful work.

Q2: What's a typical power factor for motors?
A: Induction motors typically have power factors between 0.8 and 0.9 when fully loaded, lower when lightly loaded.

Q3: How do I measure line current?
A: Use a clamp meter to measure current in any one of the three phase conductors.

Q4: Why use line-to-line voltage?
A: In 3-phase systems, line-to-line voltage is the standard measurement between any two phases.

Q5: How does this differ from single-phase calculation?
A: Single-phase uses P=VI×PF/1000 without the √3 factor.